If you're currently living on our pale blue dot, you should thank it for becoming inhabitable for us human folk. Specifically, you should look down and thank its mantle because scientists are saying that Earth's cooler mantle allowed it to develop oxygen. You know, that thing we breathe to live.

Researchers from Princeton University published a report in Nature that claims that our planet's mantle was perfect for Earth's Great Oxygenation Event which occurred over 2.5 billion years ago and lasted around 900 million years. This was the period where "oxygen levels in the atmosphere exploded and eventually gave rise to our present atmosphere."

That all sounds very important! But why was the Earth's mantle so crucial to the GOE? Because 2.5 billion years ago was when there was a sharp drop in mantle melting, the mantle (the layer between the Crust and the Core) stopped getting as hot which gave room for changes to occur. C. Brenhin Keller, lead author, and Blair Schoene, assistant professor at Princeton, wrote in the report that because of the decline in mantle melting, it also, decreased the melting of the Earth's crust and according to Futurity.org, "in turn reduced the output of reactive, iron oxide-based volcanic gases into the atmosphere. A lower concentration of these gases—which react with and remove oxygen from the atmospher—allowed free oxygen molecules to proliferate."